/* If the host doesn't support IPv6 try fallback to IPv4. */
if (s < 0 && address_family == AF_INET6) {
address_family = AF_INET;
s = socket(address_family, SOCK_STREAM, 0);
}
/* If the host doesn't support IPv6 try fallback to IPv4. */
if (s < 0 && address_family == AF_INET6) {
address_family = AF_INET;
s = socket(address_family, SOCK_STREAM, 0);
}